8 Hour Review - MTD Cub Cadet RZT SX54

wrldtvlr

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1.5 acres of unimproved 20 degree slope grass
- Unimproved means ground squirrel mounds, pot holes, small water erosion channels
- multiple planes with ridges to cross and about a half acre of mesa on top
- either a berm or ditch along the bottom boundary with no runout space
- in short, a challenge

Tried a couple of tractor mowers, including a ToolCat with mower attachment but the pucker factor was too high. A self propelled walk behind mower works, but takes about 8 hours and a couple gallons of ice tea. Lap bar Zero Turns are typically not usable for anything above 10-15 degrees. Even then, because the front wheels caster, the rear drive wheels don't follow the track on a slope and tend to dig up the turf. The RZT mowers have steerable front wheels synchronized with the drive wheels that greatly reduce this.

The RZT SX54 was only affordable consumer mower I could find that was actually rated for a 20 degree slope in the manufacturer specs. The SX models replaced the S models a few years ago. Apparently the only differences were some control positions. Functionally the S and SX are supposed to be the same.

By the way - I tried the wood 2x4 and level technique for measuring slope. That works, but the RZT operators manual has a very simple folded sheet of paper template that works just as well if all you need is a go/nogo decision.

So, let's start the walk around

As mentioned earlier, this is a true zero turn mower with a steering wheel, not lap bars.

The control column can be adjusted to one of two positions. Fully up makes entry/exit a little easier. Down is better for operation. A small center foot pedal controls the column lock, so it's easily changed. The seat is comfortable enough and slides forward or backward as needed. Armrests are standard, but if you are doing slope cutting, you'll want them up and out of the way. There's a headlight on the column for mowing at dusk. Not sure if that is all that useful. Likewise, there are a couple of molded storage pockets, a 12v charger and cup holder.

The front wheels are semi-pneumatic, so no flats.

There are 10 zerk fitting grease points. Two are under the center frame for the control linkage, two on each front post bearing, one on each front wheel bearing and one on each mower deck wheel. All are easy to access.

Note that six of the 10 grease points are blind. The only ones you can actually see the grease come out are the center linkage points and the mower deck wheels. I noticed that some of the fittings on my unit had never been factory greased, so it's definitely worth doing before your first cut.

Operator controls are easy to reach. The online engine manual says it is EFI, but there is a choke control. The keyswitch has 4 positions: Off, Reverse Enable, On and Start. More on this later.

Really surprised at how much I like the Bluetooth enabled hour meter. It pairs up with a free app for your smartphone and gives a good indication of when each maintenance item needs to be accomplished. Of course you have to be OK with MTD getting that usage data as well. The downside is that it doesn't always seem to recall login details so you have to log in each use and the app needs to be opened while the mower is running to update the hours.

The left pedal is the brake. Haven't used it much except when setting the parking brake with one of the two small center pedals. Foot off the throttle seems to stop the mower just fine. The two pedals on the right control forward and reverse speed. Press harder, go faster.

The deck level control is easy enough to use. Each detent represents about 1/2 inch. Range is between about 1 and 4.5 inches.

There's a 2.8 Gallon gas tank. Really like the visual level indicator so the cap doesn't need to be removed. The engine does go through a fair amount of gas - about 2 hours to the tank. Be nice if the RTZ had dual fuel tanks like the Z-Force, but that's what the extra $2K gets you I guess.

The welded mower deck has three blades with one quick attach hose cleanout on the left side. The rubber mower shield comes with a metal shipping brace that you'll want to keep as it makes cleaning, storage and trailering easier. By the way - an RTZ mower with 54" mowing deck is well over 60" wide. A 4x8 trailer won't work.

The seat tilts up for maintenance with access to the battery, oil filter and oil drain port. The 54 inch deck version of the RZT comes with a 21HP Kawasaki V Twin motor. It's not quite as smooth as Honda lawn equipment engines I've used, but it's not bad. It does have an oil pump and is rated for slope operations.

The mower comes with a vinyl extension tube that fits over the drain port. Just attach the tube and twist the port to open. Be sure to place a rag or shop towel under the port before changing the oil or filter.

The oil filter cross references to a number of generic filters on Amazon, so it's not necessary to buy expensive Cadet or Kawasaki branded filters. However, the generic filters may not be exactly the same size as the Kawasaki branded filters. The generic ones I ordered were slightly shorter and narrower than Kawasaki branded filters. They did fit though. You might find a better match by using the Kawasaki part number on the filter rather than the MTD number in the manual. Of course the problem with all oil filters is that it's impossible to judge the quality without running them through a lab.

Very easy to open the air filter cover.

There's an inexpensive tow bracket available for garden trailers or spray tanks that attaches behind the muffler. The RTZ is spec'd to tow up to 250 pounds.

Rear tires are good sized with turf treads. I've noticed they do pick up wet cut grass and dirt. If that happens, you'll have racing slicks with limited traction.

Not a fan of water cleanout ports. This mower only has one port even though the manual said there are two. Water ports seem to create a huge mess and don't get much grass or dirt out, even when cleaning immediately after cutting. I ended up using a power washer and even that wasn't enough. Ended up using a ramp and manually cleaning things out. If you do use the wash port, be sure to drop the deck to the lowest position and wash on a hard surface. That creates more of a wind tunnel effect. The mower blade safety switch means you have to stay seated while cleaning. Theoretically.

The manual says to not use water for cleaning anything other than the underdeck area. That's just not realistic. Be smart, don't spray water directly on the engine, spindles or electronic controls and keep the grease fittings well lubed.

Aside from the ineffective wash port, the other criticisms I have are the reverse operation safety switch, oil filter and drain and the mower deck design.

In normal operating mode, shifting into reverse immediately kills the blades. To get the blades moving you have to stop reversing and then cycle the PTO switch.

There is a reverse operation allowed position on the key switch. If after starting, you place the key in that position and press a confirmation button, the blades will continue to operate when moving forward or backing up. However, if you set the parking brake and momentarily get off the mower, the whole activation process has to be repeated. Really annoying.

The welded mower deck has rather large openings through the top of the deck that allow a ton of grass clippings and dirt to build up by the spindles and belts. The safety covers over the belts are also quite open. Suspect that was done to make cleaning easier, but it also contributes to debris buildup. Seems like there could have been a better design.

Changing the oil is a real pain. The drain tube provided is far too short and needs to be twice as long. Buy a half inch inside diameter replacement at your local big box store as soon as possible.

Not sure what species of gorilla Kawasaki has working their production line, but the oil filter was incredibly hard to twist off. Didn't want to use the old screw driver through the filter trick, but eventually with a strap, screwdriver and as hard a force I could muster, I was able to get the factory filter off.

Be sure to have a large shop rag stuffed under the filter before removing it. There will be a lot of oil draining out. A fill funnel will also be helpful. Old shop trick - if you don't have a fill funnel, you can twist newspaper into a funnel and dispose of it afterwards.

The factory air filter did not come with a foam pre-filter. Most of the aftermarket filters have this. Make sure you order the correct air filter that takes a hose clamp. Some of the oil / fuel / air filter combo packs do not have the correct air or fuel filter.

With about 8 hours on the clock, I'm not ready to give the RZT a final grade. One conclusion I quickly came to - do not do steep slopes with even the slightest hint of moisture in the grass or soil. The RZT has no problems with 20 degree slopes if the are dry. Damp? Be prepared to change your underwear. When dry, aside from the lean angle things are going well.

That's it - hope this helps.
 
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wrldtvlr

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And just to expand my comment on oil filters...

I did some searching for articles that might explain the difference between cheap and branded filters. This one was the best I found.The tl;dr is that cheap filters have smaller flow holes and cheaper components (filter material, gaskets, springs). When people were changing oil in their cars every 3000 miles or less, you could probably get away with using a cheap filter. Now that synthetic oil allows running 7500 miles or more, having a filter that switches over to bypass mode or filter media that starts to dissolve isn't such a good idea.

I'm assuming the same thing applies to mower engines. The manufacturer has a vested interest in having the motor run as long as possible. Doesn't make sense to me to save $8 on a once a year filter change. Attached are photos I took of filters I recently bought on Amazon. You can see the generic filter is smaller (i.e. less media) and has fewer flow holes in the base, when compared with the Kawasaki filter.
 

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wrldtvlr

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And a follow-up on the EFI vs carbureted engine, it's a bit annoying. If you look at the RTZ SX 54 manuals on the Cub Cadet site, the engine manual clearly states the engine is a 679 cc EFI OHV Vertical Shaft Engine. Manufacturer isn't specified, but the design is clearly Kawasaki. However, the manual provided with the mower and also on the Kawasaki site matches the actual mower engine, which is 726cc carburated engine.

Interestingly enough, on the Kawasaki web site, they show three versions of this engine (FR651V, FR691V and FR730V), all carburated, all same displacement, but three different HP ratings (21.5, 23 and 24HP). Not quite sure how they manage that.
 
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Mower King

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And a follow-up on the EFI vs carburated engine, it's a bit annoying. If you look at the RTZ SX 54 manuals on the Cub Cadet site, the engine manual clearly states the engine is a 679 cc EFI OHV Vertical Shaft Engine. Manufacturer isn't specified, but the design is clearly Kawasaki. However, the manual provided with the mower and also on the Kawasaki site matches the actual mower engine, which is 726cc carburated engine.

Interestingly enough, on the Kawasaki web site, they show three versions of this engine (FR651V, FR691V and FR730V), all carburated, all same displacement, but three different HP ratings (21.5, 23 and 24HP). Not quite sure how they manage that.
I'd really like to see a pic of your engine from, standing behind the mower, and the model & serial # off the engine, if it's a Kaw, it will have a code #
 

wrldtvlr

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I'll shoot a photo from the rear later today when I have a chance to roll the mower out of storage. I had a shot of the engine label.
 

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wrldtvlr

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I'd really like to see a pic of your engine from, standing behind the mower, and the model & serial # off the engine, if it's a Kaw, it will have a code #
As you can see, definitely a carbureted engine. When you look at the RZT lineup, it's interesting to see the engine for each model. The smaller mower decks appear to use the 679cc EFI engine. Only the 54" model uses the 726cc carburetor Kawasaki. f4.jpg
 

upupandaway

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has fewer flow holes in the base

No offense but a quick lookup of oil flow through a 3/8" pipe alone will handle 1.89cu ft/min. and there are how many holes in the standard filter?
Being it is not a 4liter engine it won't be pumping anywhere close to the limit. Personally i use a Wix car filter on my Kawi because it is flat cheaper than paying >$10 to a dealer and not for the gpm flow.
 

wrldtvlr

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No offense but a quick lookup of oil flow through a 3/8" pipe alone will handle 1.89cu ft/min. and there are how many holes in the standard filter?
Being it is not a 4liter engine it won't be pumping anywhere close to the limit. Personally i use a Wix car filter on my Kawi because it is flat cheaper than paying >$10 to a dealer and not for the gpm flow.
No offense taken and I'm not a lubrication engineer. Just summarizing my take from the linked article - that sometimes filter manufacturers intentionally reduce the flow through a filter to compensate for less effective media. One sign of a lower quality filter is the number of flow holes. For me, the savings from an imported filter doesn't seem to be worth it. They also conclude that domestic Wix filters are very high quality and if you can get a deal, so much the better.
 

Mower King

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I'll shoot a photo from the rear later today when I have a chance to roll the mower out of storage. I had a shot of the engine label.
Thanks.....I was just trying to figure out what eng you had. You said something about a Kaw EFI but had a choke knob, so I had to check it out. Anyways....from your pics you have a Kaw FR651 carbureted engine rated at 21.5 hp. Cub Cadet does have a EFI eng that comes on them that is built "overseas".....surprisingly they run smoother than the USA built engines, I don't know about reliability yet but, we have sold some of them so, time will tell!
 

wrldtvlr

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Thanks.....I was just trying to figure out what eng you had. You said something about a Kaw EFI but had a choke knob, so I had to check it out. Anyways....from your pics you have a Kaw FR651 carbureted engine rated at 21.5 hp. Cub Cadet does have a EFI eng that comes on them that is built "overseas".....surprisingly they run smoother than the USA built engines, I don't know about reliability yet but, we have sold some of them so, time will tell!
Yeah, my confusion stemmed from the Cub Cadet documents web page for the RZT SX54. The only engine manual they've posted is the EFI engine for the smaller deck sizes, which doesn't apply to the 54" deck model. Glanced at the cover and assumed that was the engine on my machine. I'd send them a note, but I don't see any contact information for their web page group.
 
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